Negative effect of science?
There is no negative effect as long as religion is included in the equation, one cannot survive without the other. To deny one is to place disbelief in the other. We can neither disprove creationism and or evolution. Where does that leave us, are we familiar with the apes or are we the result of two unknowing entities in a garden, somewhere lost in our subconscious. As stewards of this planet, we need to know, and we need to know now.
Science is like a tool and if the people using it have negative intentions, then it may yield negative results. Weapons of mass destruction are made possible because of advancements in science and technology. Also, one unintentional effect of the advancement of science and technology is global warming.
Science does not in itself have a negative effect on agriculture or on anything. Science is knowledge, which can be used wisely or foolishly. People who use scientific techniques in the pursuit of short-term agricultural productivity, without considering long-term results, will have problems in the long term. That is not the result of science, it is the result of short-sightedness.
A "Negative Experiment" is one where the expected result of the experiment is not found. These experiments are critically important and represent important work in Physics. The Michelson-Morley experiment, a "negative experiment" is one of the most important in the history of science. It was an test to measure the influence of the presumed etheric medium on a beam of light. No effect was found. Thus no ether.
It doesn't. There's no such thing, not in scientific terms. Some people might use the phrase as a metaphor but business and politics is full of scientific, or pseudo-scientific, terms used metaphorically by people who clearly do not understand basic science! Certain forms of energy, such as electrical current, have polarities; but the negative pole of a circuit does not mean electrical energy is "negative".